Kurma incarnation is lord vishnu avatar in form of Tortoise.The worshipper of Kurma shaligram gets immense PERSEVERANCE, strong will power, patience, wealth and happiness in his life. The kurma shaligram also works as a shield against all evil forces.

The person who offers a daily service for the salagrama stone will be freed from the fear of death, and he will cross over the stream of births and deaths.

As Vishnu abides in these stones, all the gods dwell there, all the benevolent spirits and indeed the fourteen worlds reside in these stones.Hence, we have it as an assurance from Vishnu himself that whoever worships the salagrama-stone even once will surely be liberated: and also will obtain all prosperity here, while alive. (Padma-purana, Uttara-khanda, 127)